go/doc: print only one newline between paragraphs Fixes issue 2595.
go/doc: print only one newline between paragraphs
Fixes issue 2595.

R=golang-dev, gri
CC=golang-dev
http://codereview.appspot.com/5544068

tv42/old-go,tv42/old-go,apparentlymart/golang,pombredanne/go-deleteme,apparentlymart/golang,pombredanne/go-deleteme,dsriram/golang,tv42/old-go,apparentlymart/golang,dsriram/golang,dsriram/golang,apparentlymart/golang,pombredanne/go-deleteme,dsriram/golang,dsriram/golang,tv42/old-go,pombredanne/go-deleteme,gnanderson/go,pombredanne/go-deleteme,tv42/old-go,gnanderson/go,pombredanne/go-deleteme,tv42/old-go,dsriram/golang,apparentlymart/golang,tv42/old-go,apparentlymart/golang,pombredanne/go-deleteme,gnanderson/go,gnanderson/go,gnanderson/go,gnanderson/go,gnanderson/go,apparentlymart/golang,dsriram/golang